78 



VE TBRINAR r DENTAL SC /.' f i /: A' 1 '. 



FIG. 2O. 

 GENERAL CARIES OF A 



Caries of the neck (cervix) 

 of the tooth is seen in those 

 horses whose teeth are wide 

 apart, and is caused by the food 

 remaining in the interspaces and 

 by decomposition exciting in- 

 tlnmmation in the periodental 

 membrane. 



Caries commencing at the 

 crown or table, is due to a por- 

 tion of the dentine losing its vital- 

 ity, and the power of resisting 

 TOOTH. the chemical action of the fluids 



of the mouth; a portion of the enamel of the crown 

 may be fractured by the animal accidentally biting a 

 piece of hard stone or metal contained in his food. 

 Mere fracture of the enamel is not sufficient of itself 

 to lead to caries of the teeth of the lower animals, 

 foi it is a substance that is gradually worn off by the 

 attrtion of the teeth continually going on during 

 mastication; but the pressure which has been suf- 

 ficiently great to cause fracture of the enamel, may 

 at the same time have caused such an amount of 

 injury to the subjacent dentine, that it dies and pro- 

 gressively becomes decomposed. 



SYMPTOMS. There will be quidding of the food, 

 in some instances the animal will pick up the hay, 

 chew it until it is formed into a bolus thoroughly 



